Investigation of the dynamic local skidding behaviour of rollers in cylindrical roller bearings

Skidding has a great influence on the reliability and the life of rolling element bearings. The previous research of bearing skidding mainly focussed on the gross skidding of bearings under severe conditions. However, the local skidding of rolling element also exists and cannot be ignored when bearing normally runs at steady state. In this paper, considering the discontinuous contact between the roller and the cage, the Hertz contact between the roller and races, lubrication, centrifugal effects and the cage pocket clearance, a nonlinear dynamic model is established to investigate the local skidding behaviour of a roller in cylindrical roller bearings. The equations of the dynamic model are solved by the fourth-order Runge–Kutta algorithm and verified by comparing simulation results with the published experimental data. The results show that the local skidding of the roller still noticeably exists in bearings even when the gross skidding can be ignored, especially on the inner raceway. The local skidding at the entry of the loaded zone may cause the smearing on the raceway surface. However, it can be found that the probability of the local skidding of the roller will be decreased by increasing radial load and reducing the bearing rotational speed. The cage pocket clearance would induce violent fluctuations on the roller rotational angular velocity as well as on the sliding velocity. Furthermore, it can generate extraordinary impact forces between the rollers and the cage. Thus, the cage pocket clearance should be carefully considered in the design of bearings.